[WIP] First pass to add all attrs in one shot, as opposed to filtering by class.

We needed to add a hook for Widget, which for it's HTML_PARSER needs srcNode, contentBox
set up as attributes, before the rest of the attributes are added, since it merges
information from the markup, into the userConfigs (since they're logically equivalent),
and uses get("srcNode") to figure out what to use for the srcNode to parse.

This is a bit of an edge case.

Not sure if this will be the final hook for Widget, and potentially similar edge cases,
hence the "first pass".

Performance
-----------

A slight performance gain at the Core level (we weren't expecting anything substantial,
since the basic looping/isolation costs still remain):

Prior Commit (Chrome 21/MacOS):

BaseCore x 140,880 ops/sec ±1.11% (91 runs sampled)
MyBaseCore x 134,122 ops/sec ±1.54% (93 runs sampled)

This Commit (Chrome 21/MacOS):

BaseCore x 153,260 ops/sec ±1.89% (94 runs sampled)
MyBaseCore x 152,053 ops/sec ±1.41% (91 runs sampled)

Testing
-------

All current tests pass:
✔ [Total]: Passed: 10895 Failed: 0 Total: 10992 (ignored 97)

Will add a test for the actual use case this should fix (overriding setters,
which refer to subclass attrs).
Added tests for the subclass override attrs ref issue, which the
filterAttrCfg removal is supposed to fix.

Confirmed that it fails before the fix, and passes after it.
Removed short term workarounds added for out of order attribute
handling just before 3.10.0 release, and put proper fix in place,
along with tests. This commit goes along with the commit to add
all attributes in one shot (see commit: 002a4aa5b39c01).

Testing (with yogi test --no-cli):

With 3.10.1 all newly added tests fail.
With this commit **all** library tests, including the new ones, pass
API Docs for add all ATTRS at once change
Added HISTORY.md for 'add all ATTRS at once' change
Merge branch 'dev-3.x' into base-remove-filterattrs
Merge branch 'dev-3.x' into base-remove-filterattrs
Fix for the Charts issue with seriesKeys and the internal explicitly set flag,
now that Attribute/Base order of operation issues have been sorted out.

Testing:
*All* library unit tests now pass (including latest charts code)
Merged latest dev-3.x and fixed base HISTORY.md conflict
Merge branch 'base-remove-filterattrs' into dev-3.x (--no-ff, just in case)
Build for filterAttrs removal

Includes the core changes to Attribute, Base to add all attributes in
one shot, as opposed to a class at a time, plus the related changes
to Widget HTML Parser, and Charts seriesKeys support to keep things
working.

Testing
-------

*All* library tests pass:
✔ [Total]: Passed: 11055 Failed: 0 Total: 11146 (ignored 91)

Additionally, all currently passing example functional tests pass also.

A few functional tests failed before this fix, and continue to fail
(a couple of 'test' examples, and the 'datasource-get' example)
Merged upstream/dev-3.x and fixed base/HISTORY.md merge conflict, prior to push